Field of the Invention
The present invention relates to a battery module, and more particularly to a battery module applied to an electric vehicle that travels by driving a motor with power of a battery.
Description of Related Art
There has conventionally been known that an assembled battery formed by collecting plural battery cells, i.e., a so-called battery module, is used as a battery for supplying power to a motor of an electric vehicle.
JP-A No. 2001-236937 describes a battery module formed by stacking plural tabular battery cells with a certain thickness, wherein both end faces of a battery cell group are sandwiched between a pair of plate-like members (constrained plates), and the plate-like members are fastened by a threaded connecting rod to apply pressure thereto, in order to prevent an expansion of each battery cell caused by a secular change or misalignment between the battery cells due to the expansion.
However, the technology described in JP-A No. 2001-236937 has a problem that the size of the whole battery module is liable to increase, since four connecting rods are mounted along the outer wall surface of the battery cell group, and a seating surface of a fastening nut for fastening the connecting rod has to be formed on the outer periphery of the constrained plate.